This invention relates generally to a gate system for use with a storm drain of the type typically found in the curb of a street. More particularly, this invention relates to such a system which during periods of low water flow is in a closed position to effectively prevent debris from entering into the storm drain, but which during periods of high water flow opens to allow the maximum amount of water to enter into the drain to alleviate the accumulation of water in the street and the surrounding areas.
What to do with excess runoff rain water has been an issue for urban planners and dwellers for a long time. Even in arid regions, the occasional heavy rainfall will create large volumes of run off that must be channeled effectively or flooding resulting in impassable roads at least or the loss of property and lives at worst may occur. In areas of high annual rainfall, effectively channeling that rainwater away from streets and homes is an absolute must
For this reason, almost every city in the civilized world has an extensive underground storm drain system. And the most common inlet to the entire system is the ubiquitous curbside opening that is built into the sidewalk curb along the street. Those openings typically lead to a rather large underground chamber, often called a vault, at one end of which there is a conduit that leads to the main storm drain pipe that is usually set under the paved road adjacent the vault.
These drain systems have proven very effective in channeling runoff storm water away from the streets and populated areas, and usually into an adjacent river or into the ocean. However, another ubiquitous part of urban life—street debris and litter—also finds its way into the storm drain system. For example, some cigarette smokers seem to believe that their cigarette butts are not litter to be deposited in a trash can, but something that can be thrown on the ground wherever they happen to be when they must discard the cigarette—thrown into the gutter as they walk along the sidewalk, or thrown out of the car as they drive along. These cigarette butts, which are not environmentally friendly and do not naturally degrade easily, invariably end up in the drain system and then into the river or ocean into which it drains. Other trash, from paper cups to hamburger wrappers to envelops, all find there way into the gutters, drain systems and ultimately river and ocean. And this is just the man-made debris. Naturally debris such as leaves and twigs are also commonly found in streets and gutters, and then make their way into the storm drain system when it rains, or when water from some other source makes its way into the street.
It is not just the introduction of these items into the drain system that is a problem. Most storm drain systems ultimately empty directly into a nearly body of water, often a river or the ocean. Also, the systems rarely include any type of intermediate water treatment facility, so what goes into the drain system usually ends up in river, lake or ocean, where it is unsightly and can be toxic.
Because the introduction of trash and other debris into the storm drain system is such a common occurrence, many street side drains are constructed with a sizeable open chamber into which the storm drain opening leads, with the conduit to the under-street pipe located at one end thereof. The purpose of this is to try to trap as much of the debris as possible in the vault, and only allow the water to run-off into the system. This has proven only partially effective. First, so much trash is often introduced into the vault that much of it gets into the system anyway. This is particularly true if there is an accumulation of trash in the vault when there is a heavy rainfall or other heavy flow of water into the vault. Second, this arrangement necessarily requires that the vault be periodically cleaned, and cleaning the vault cannot of course be done by the usual street sweeping equipment, but requires an entirely different piece of equipment with strong suction capability to literally vacuum the trash from the vault. Third, this arrangement is designed to allow the trash to accumulate in the vault in between cleanings, such that in a worst case scenario, the accumulated trash becomes so large that the drain becomes plugged wholly or partially, and flooding in the area occurs when it rains.
In light of these issues, various attempts have been made to prevent trash from getting into drain. For example, in some places, a sizeable plate has been securely attached over the drain opening, leaving only a little space for water to flow. This solution does prevent much of the trash from entering into the drain, but it also prevents much of the water as well, and essentially defeats the purpose of the large drain opening that was intended to prevent flooding during heavy water run off. Therefore, other attempts have been made to design a storm drain gate that would remain closed during periods of low water run off, but which would automatically open in periods of heavy water run off. One recent example is U.S. Pat. No. 6,972,088, to Yehuda, in which a Pivotal Gate For A Catch Basin Of A Storm Drain System is disclosed. That system uses a rather complex system involving a rotatable paddle wheel and interconnected wires that interplay to open the gate when sufficient water begins to flow into the drain. While it appears workable, this system may not be desirable for widespread installation given its complexity, which translates into higher initial cost and higher cost of upkeep. It is a given in any piece of machinery that the more moving and complex the component parts, the more costly to manufacture and install, and the more costly to maintain, and more likely to malfunction. Other prior art devices suffer from one or more of these drawbacks, as the design goals of simplicity, ease of installation, durability, low maintenance, and high effectiveness are difficult to achieve.
Therefore, there exists a need in the art for such a simple, effective gate system.